1. Field of the Invention
The present invention relates to a binder, and in particular, to a binder in which first and second binding members for forming closed loops can be rotated in the open/close direction, and the closed loop can be released with a slight operating force.
2. Description of the Related Art
Conventionally, a binder used for a ring file or the like comprises a base fixed to a back cover or to a position adjacent thereto of the file or the like, a pair of first binding members disposed at two positions in the longitudinal direction on the base, and a pair of second binding members positioned at the opposite sides to these first binding members and are brought into contact with the respective front ends of the first binding members. The first and second binding members are connected respectively at the base side thereof by first and second connecting plates; thereby the first binding members and second binding members are adapted to be capable of rotating in the open/close direction respectively.
However, in the known binder as described above, such an arrangement is adopted that, when the binding members are in the closed state where closed loops are formed, the first and second connecting plates act to prop the respective binding members so as to maintain the closed state thereof. Due to this, when opening the binding members, since it is necessary to give a strong external force to the binding members to forcibly open the front ends between the first and second binding members, there resides in such an inconvenience that operation thereof is difficult for a user who is poor in operating force.
On the other hand, when the binding members are operated from the open state to the closed state, such an inconvenience that the binding members are closed snapping a large sound is created since the spring force accompanying the angle change of the connecting plates act strongly to maintain the opened state when the binding members are rotated in the close direction exceeding a specific angle, and it causes not only to emit an annoying noise but also to render such a fear that a finger might be pinched during closing operation to the user.